Maximum number of pairs allowed

The maximum number of pairs depends on the storage system.

The following table lists the maximum number of pairs allowed for each storage system.

65,280 pairs (maximum)
VSP G800, VSP F800 8,192 pairs (maximum), 4,096 pairs or fewer, recommended
VSP G400, VSP F400, VSP G600, VSP F600 4,096 pairs (maximum), 2,048 pairs or fewer, recommended
VSP G200 2,048 pairs (maximum), 1,024 pairs or fewer, recommended

The maximum number for your storage system is limited by:

  • The number of cylinders in the volumes, which must be calculated.
  • The number of bitmap areas required for Universal Replicator data and journal volumes. This is calculated using the number of cylinders.

    If the volume size is larger than 4,194,304 MB (8,589,934,592 blocks), the bitmap area is not used. Therefore, it is not necessary to calculate the maximum number of pairs when creating UR pairs with DP-VOL whose size is larger than 4,194,304 MB (8,589,934,592 blocks).

    NoteWhen SOM 1050 or Advanced System Setting No. 5 is enabled, the bitmaps for all pairs created with DP-VOLs smaller than 262,668 cylinders (4 TB), are managed in hierarchical memory and not in shared memory. In this case, the bitmap area in shared memory is not used, so you do not need to calculate the maximum number of pairs when SOM 1050/Advanced System Setting No. 5 is enabled.
CautionThe bitmap areas that are used for UR are also used for UR-MF, TC, TC-MF, and GAD. If you use UR with any of these products, use the total number of each pair’s bitmap areas to calculate the maximum number of pairs. In addition, if UR and TC share the same volume, use the total number of both pairs regardless of whether the shared volume is primary or secondary.